Primecoat compositions for proteinaceous substrates and methods of priming proteinaceous substrates therewith

ABSTRACT

Compositions containing a solution of a polyfunctional aziridine component in a non-reactive solvent, and methods of applying such compositions to proteinaceous substrates, such as fingernails and toenails, to provide primed substrates which may be further coated.

BACKGROUND OF THE INVENTION

The reparation, adornment, and prosthetic extension of proteinaceousstructures, namely, human fingernails and toenails and livestock hoofs,has been a common practice for centuries. Fingernails are currentlyknown to be coated with multicolored nitrocellulose lacquers, repairedwith cyanoacrylate adhesives, and extended with the use of acrylicmonomer and polymer slurries or doughs that cure by peroxide/amine freeradical mechanisms. The nitrocellulose-based lacquers currently in wideuse possess the resiliency and toughness to perform this function well.However, such lacquers require very strong and pungent solvents tosolvate the nitrocellulose. Thus, there have been several attempts toprovide water-based polishes as substitutes for nitrocellulose-basedlacquers. Both nitrocellulose-based lacquers and water-basedformulations suffer to varying degrees from premature failure asdecorative nail coatings. Such failure can take the form of wear at thetip of the nail, chipping from the ends and sides of the nail, toscratching anywhere on the nail. All three modes of failure are theresult of catastrophic failure of adhesion between the nail polish andthe nail plate (i.e., the proteinaceous substrate).

While cyanoacrylate adhesives for fingernail repair are relativelyadherent to a fingernail plate, the acrylic materials employed for thepurpose of creating an artificial fingernail prosthesis are not. Onlyafter treatment of the fingernail surface with an unsaturated carboxylicacid, such as methacrylic acid (current commercial embodimentscontaining in excess of 70 percent methacrylic acid), will such acrylicmonomer and polymer slurries or doughs adhere to the nail plate. Suchharsh treatment on a relatively fragile surface poses a serioustoxicological hazard due to the corrosive nature of the unsaturatedcarboxylic acids. Other unsaturated carboxylic acids presently beingused in such applications include either alone or in part, acrylic acidand beta-carboxyethyl acrylate. Lower concentrations of theseunsaturated acids pose a decreased danger to the intact fingernailsurface; however, at such lower concentration the adhesion of theacrylic monomer and polymer slurry is minimized or lost completely. Ananalogous situation exists when attempting to repair a split orfractured hoof in that without the application of the corrosive andpossibly toxic levels of unsaturated acids, very poor adhesion results.

Currently, the most widely used method for improving adhesion of nailpolishes and prosthetic materials to proteinaceous substrates, such asfingernails and hooves, has been the physical abrasion and roughening ofthe proteinaceous substrate surface with a file, sand-paper-like, orother abrasive material, and/or the application of unsaturatedcarboxylic acid solutions (known in the artificial fingernail art asprimers), followed lastly by the application of the polish or prostheticmaterial.

The disadvantages of such prior art adhesion-improvement methodsinclude: (1) too much physical abrasion or roughening of theproteinaceous substrate, particularly a living fingernail, can beharmful to the substrate and surrounding cuticles; (2) in the area ofhoof binding, cracks and fissures in the hooves are not readily abradedor roughened due to the inaccessibility of the surface to such abrasivematerials and methods; (3) the unsaturated carboxylic acids that areoften used (acrylic acid and methacrylic acid), either alone at fullconcentration of in combination with other diluents, are highlycorrosive and can severely damage the protein of a fingernail or hoof orthe underlying or surrounding living tissue; and (4) even with suchharsh surface preparation as described above, the adhesive bondsobtained with such methods are poor and all too often inadequate toretain the polish or prosthesis for sufficient periods of time or understress, thus causing the polish to chip and the prosthesis to break offin whole or in part.

Various prior art adhesive compositions and fingernail treatments havebeen suggested for improving the bond between coatings and the nailplate. For example, fingernail strengtheners deposited from solution areknown, but do not improve bond strength. Materials and methods forobtaining high bond strengths to dentin, which is a partiallyproteinaceous substrate, have been described, but are the additionreaction products of, for example, pyromellitic acid dianhydride and2-hydroxyethyl methacrylate (PMDM), the addition reaction product of3,3′,4,4′-benzophenonetetracarboxylic dianhydride and 2-hydroxyethylmethacrylate (BTDA-HEMA) and 4-methacryloxyethyltrimellitic anhydride(4-META). Such materials contain harsh unsaturated compounds and alsoexhibit inferior bond strength improvement compared to the presentinvention.

In general, prior art materials and methods suffer from a poorcombination of toxicity, odor and/or poor adhesion-promotingperformance.

BRIEF SUMMARY OF THE INVENTION

The present invention relates materials and methods which provideincreased adhesive bond strength between: adhesives, coatings orcomposites, on the one hand; and proteinaceous substrates such asfingernails, toenails and livestock hooves, on the other hand. Thepresent invention includes materials and methods for providing primedproteinaceous substrates upon which topcoats, composites, adhesivesand/or prosthetic extensions can be applied with improved adhesion.Moreover, the materials and methods of the present invention providenontoxic, odorless, and improved bond strength between adhesives,coatings or composites, and proteinaceous biological substrates and area significant improvement over the prior art.

Various embodiments of the present invention are directed tocompositions which comprise a solution of a polyfunctional aziridinecomponent in a non-reactive solvent capable of solubilizing thepolyfunctional aziridine component. Non-reactive solvents suitable foruse in the various embodiments of the present invention are non-reactivewith the polyfunctional aziridine component. As used herein,“non-reactive solvent,” in its broadest sense, refers to any solvent inwhich a polyfunctional aziridine component is soluble and which does notreact with the polyfunctional aziridine component. Preferably,non-reactive solvents for use in the various embodiments of the presentinvention are polar, aprotic solvents.

Various preferred embodiments of the present invention are directed tocompositions which comprise a solution of a polyfunctional aziridinecomponent in propylene glycol mono-methyl ether, wherein thepolyfunctional aziridine component comprises pentaerythritoltris(3-aziridinopropionate), and wherein the polyfunctional aziridinecomponent is present in an amount of 2.5 to 7.5% by weight, based on thesolution.

Various other embodiments of the present invention are directed tomethods which include: (a) providing a solution of a polyfunctionalaziridine component in a non-reactive solvent; and (b) applying thesolution to a proteinaceous substrate. Further embodiments of thepresent invention are directed to methods which include: (a) providing asolution of a polyfunctional aziridine component in a non-reactivesolvent; (b) applying the solution to a proteinaceous substrate; (c)removing the non-reactive solvent from the solution applied to theproteinaceous substrate to provide a primed substrate; and (d) applyinga topcoat composition to the primed substrate.

In various preferred embodiments of methods according to the presentinvention, the non-reactive solvent comprises propylene glycolmono-methyl ether, the polyfunctional aziridine component comprisespentaerythritol tris(3-aziridinopropionate), the polyfunctionalaziridine component is present in an amount of 2.5 to 7.5% by weight,based on the solution, and the topcoat composition comprises awater-based nail polish.

Briefly, methods in accordance with the present invention can preferablybe carried out by applying, e.g., via brushing, a solution of apolyfunctional aziridine component in a non-reactive solvent to aproteinaceous substrate such as, for example, a fingernail, allowing thenon-reactive solvent to evaporate and subsequently applying a topcoat tothe primed substrate. Thus, after priming the surface of a proteinaceoussubstrate with a composition according to any of the various embodimentsof the present invention, the primed surface may then be contacted withan adhesive, coating or composite providing greater adherence of suchmaterials to the primed substrate, than to an unprimed substrate.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the singular terms “a” and “the” are synonymous and usedinterchangeably with “one or more” and “at least one,” unless thelanguage and/or context clearly indicates otherwise. Accordingly, forexample, reference to “a solvent” or “the solvent” herein or in theappended claims can refer to a single solvent or more than one solvent.Additionally, all numerical values, unless otherwise specifically noted,are understood to be modified by the word “about.”

Polyfunctional aziridine components suitable for use in the variousembodiments of the present invention include compounds having two ormore aziridine functionalities, mixtures containing at least one suchcompound, and mixtures of two or more such compounds. As used herein, an“aziridine functionality” refers to an aziridine moiety (also referredto in the literature as azacyclopropane, or ethyleneimine) bound to theremaining portion of the compound at the ring nitrogen. The structure ofan aziridine functionality is shown below:

wherein either or both ring carbons may be substituted or may both beartwo hydrogen atoms. As used herein, unless a specific compound isrecited, reference to “aziridine functionality” or “aziridinefunctionalities” can mean either an unsubstituted azacylcopropane groupor an azacyclopropane wherein either or both ring carbons aresubstituted. In various preferred embodiments according to the presentinvention, aziridine functionalities present in a polyfunctionalaziridine component are unsubstituted.

Compounds having two or more aziridine functionalities which aresuitable for use in the various embodiments of the present invention canthus be represented by the following structural formula:

wherein X represents an organic residue, the azacyclopropane carbons maybe substituted or unsubstituted, and a represents a number greater thanor equal to 2. The organic residue may be linear or branched aliphatic,cycloaliphatic, aromatic, polycyclic, may be substituted orunsubstituted, may contain one or more heteroatoms, and may bear one ormore additional organic functional groups which have low nucleophilicityand bear no labile hydrogens (i.e., are non-reactive with aziridine).Thus, compounds having two or more aziridine functionalities which aresuitable for use in the various embodiments of the present inventioninclude organic compounds having two or more aziridine functionalitiesbound thereto.

Preferably, polyfunctional aziridine components suitable for use in thevarious embodiments of the present invention have three or moreaziridine functionalities. Mixtures of compounds, the mixture having anaverage aziridine functionality of greater than 2.0, can be used and canbe prepared, for example, by reaction of branched polyfunctionalacrylates and aziridine or by reaction of branched polyfunctionalalcohols and aziridinylcarboxylate compounds, such as described in R.Roesler, et al., “Review: Tris-3-(1-aziridino)propionates and their usein formulated products,” PROGRESS IN ORGANIC COATINGS, 50 (2004), pp.1-27, the entire contents of which are incorporated herein by reference.Such mixtures of compounds with two or more aziridine functionalitiescan be obtained commercially as well, such as PZ-33™ polyfunctionalaziridine, available from PolyAziridine, LLC, Medford, N.J.

In general, any organic molecule (e.g., aromatic, aliphatic,heterocyclic, etc.) containing two or more appropriate functional groupscan be converted into an aziridine-functionalized organic compound whichis suitable for use in the various embodiments of the present inventionas a polyfunctional aziridine component. Aliphatic organic compounds arepreferable and, even more preferably, branched aliphatic organiccompounds can be used as starting compounds foraziridine-functionalization. Lower molecular weight, branched, aliphaticorganic compounds, with improved solubility in water-miscible solventsand lower viscosity, can be used as starting compounds foraziridine-functionalization in various particularly preferredembodiments. For example, N-substituted aziridines can be prepared,using an organic compound containing two or more appropriate functionalgroups as a starting compound, by the addition of alkyl nitrenes todouble-bonds present in such an organic starting compound. Suitablepolyfunctional aziridine component can also be prepared by the Michaeladdition of aziridine or methyl aziridine to an ethylenicallyunsaturated moiety of an organic starting compound. Another suitablegeneral method of preparation for polyfunctional aziridine componentsaccording to the various embodiments of the present invention, which ispreferred because of the commercial availability of starting materials,is the transesterification of polyhydric branched aliphatic organicmolecules with aziridine-modified esters. One specific example of such atransesterification method is the preparation of pentaerythritoltris(3-aziridinopropionate):

a multifunctional aziridine compound, synthesized by thetransesterification of pentaerythritol with methyl3-aziridinylpropionate. Preferred polyfunctional aziridine componentsfor use in the various embodiments of the present invention containpentaerythritol tris(3-aziridinopropionate), trimethylolpropanetris(3-2-methylaziridino)propionate, and/or trimethylolpropanetris(3-aziridinopropionate). Particularly preferred polyfunctionalaziridine components for use in the various embodiments of the presentinvention contain pentaerythritol tris(3-aziridinopropionate).

In the various embodiments according to the present invention, acompound having three or more aziridine functionalities is preferablyemployed. In various even more preferred embodiments of the presentinvention, a mixture of two or more compounds having aziridinefunctionalities, the mixture having an average aziridine functionalityof greater than 2.0, is employed. In progressively more preferredembodiments of the present invention, a mixture of two or morecompounds, the mixture having an average aziridine functionality ofgreater than 3.0, more preferably greater than 3.1, even more preferablygreater than 3.2, and still more preferably at least 3.3, is employed.For example, pentaerythritol tris(3-aziridinopropionate) synthesized bythe transesterification of pentaerythritol with methyl3-aziridinylpropionate will generally result in a mixture of mono-, di-,tri- and tetra-(3-aziridinopropionate) functionalized compounds, as wellas some potential residual pentaerythritol. Preferably, the ratio ofthese species within the reaction product provides an an averageaziridine functionality of greater than 3.1, more prefereably greaterthan 3.2, and even more preferably at least 3.3.

In general, the molecular weight of the polyfunctional aziridinecomponents suitable for use in the present invention is not critical,except that the molecular weight should not be so high that thecomponent cannot be rendered into solution using standard mixingequipment (i.e., the molecular weight should not be so high that thecomponent is too viscous or insoluble in the preferred solvents). Forexample, when employing a polyfunctional aziridine component preparedvia transesterification of polyhydric branched aliphatic organicmolecules with aziridine-modified esters wherein a mixture of compoundsresults, the mixture should generally have a viscosity below 5000centipoise at 25° C., and preferably less than 4000 centipoise at 25° C.

Monomeric ethylenimine (C₂H₅N), (i.e., azacyclopropane unbound to anylarger molecule) is undesirable from a toxicity perspective.Accordingly, it is generally preferable to use polyfunctional aziridinecomponents which have a low content of monomeric ethylenimine, and evenmore preferably, polyfunctional aziridine components which have nodetectable content of monomeric ethylenimine.

Solvents suitable for use in solutions in accordance with variousembodiments of the present invention include any non-reactive solventscapable of solubilizing the polyfunctional aziridine component. As usedherein, the term “non-reactive” refers to a lack of reactivity betweenthe solvent and the polyfunctional aziridine component. Protic solventsactivate the aziridinyl group to nucleophilic ring-opening and are thusto be avoided. In this regard, as used herein, “non-reactive” refers toand includes aprotic solvents which possess weakly nucleophilic oxygenatom(s) in the form of ether and/or sterically hindered hydroxylfunctionalities which do not react with the aziridinyl groups of thepolyfunctional aziridine to any appreciable extent. Alkylation ofpropylene glycol ethers usually favors alkylation of the primaryalcoholic moiety in a step-wise process to full alkylation of bothprimary and secondary alcoholic functions. This minimizes the primaryalcoholic functionality as a source of unproductive side reactions withthe aziridinyl groups of the polyfunctional aziridine so thatmono-substituted propylene glycols can be used for purposes of thisinvention. Thus, non-reactive aprotic solvents which are suitable foruse in the various embodiments of the present invention includealiphatic alkyl mono- or di-substituted glycol ethers wherein at leastthe primary alcoholic functionality/ies is/are alkylated, e.g.,di-substituted mono- and diethylene glycols, and mono- anddi-substituted mono- and dipropylene glycols.

Solvents which are capable of solubilizing the polyfunctional aziridinecomponent will possess solubility parameters that closely match that ofthe polyfunctional aziridine. This measure of cohesive energy densityfocuses on the principle that substances which exhibit similarsolubility parameters—the sum of their non-polar interactions, polarinteractions and hydrogen bonding characteristic—are more mutuallysoluble. Solubility parameters may be calculated from chemical structurewherein the individual molar attraction constants of each functionalgroup are additive over the structural formula For the purposes of thepresent invention it has been found that the preferable balance offunctionality as determined from solubility parameter calculations ismanifest in the monoalkylated mono- and di-ethylene and propyleneglycols. Higher molecular weight alkylene glycols with a lower ratio ofhydroxyl/alkylene ether functionality do not yield solutions of thedesired clarity and are thus less preferred.

In various preferred embodiments of the present invention, suitablesolvents are additionally fast evaporating. Generally, “fastevaporating” in the context of the present invention refers to a solventwhich when applied to a proteinaceous substrate as a thin film of 10microns or less will evaporate within about 30 seconds. In variouspreferred embodiments of the present invention, suitable solvents arelow odor, odorless, or have a pleasant odor. Both fast evaporation rateand low odor emission can be related generally to the boiling point ofthe solvent. Solvents suitable for use in various preferred embodimentsof the present invention have a boiling point of about 150° C. to about250° C., more preferably 150° C. to 225° C., even more preferably 150°C. to 200° C., and most preferably 150° C. to less than 200° C. As isunderstood by those skilled in the art, as boiling point decreases,evaporation rate increases and as boiling point decreases, odor emissionincreases. Accordingly, it is to be understood that the less offensive aparticular solvent's odor is, the lower its boiling point may be in usein the embodiments of the present invention as a faster evaporation rateis achieved.

In various preferred embodiments of the present invention, suitablesolvents are low toxicity, and even more preferably, non-toxic. U.S.government regulatory agencies have identified the potential of ethyleneglycol polyethers to cause reproductive and developmental toxicity andis restricting the use of the dimethyl polyethylene glycol ethers inconsumer products beyond those that are already ongoing. Accordingly, inthe various embodiments of the present invention, alkyl ethers ofethylene glycol and polyethylene glycol are less preferred as suitablesolvents. Propylene glycols, however, do not suffer from such toxicityissues, and are thus, more preferred.

Furthermore, in particularly preferred embodiments of the presentinvention, suitable solvents are non-reactive, polar and provideexcellent solubility for the polyfunctional aziridine component, fastevaporating, low odor and non-toxic.

In various preferred embodiments of the present invention, suitablenon-reactive solvents include dialkyl ethers of ethylene andpolyethylene glycols, and monoalkyl and dialkyl ethers of propyleneglycol and polypropylene glycols, though as discussed above, ethyleneand polyethylene glycols are less preferred than propylene andpolypropylene glycols. Examples of suitable non-reactive solventsinclude, but are not limited to, dialkyl ethylene glycol ethers, dialkyldiethylene glycol ethers such as dimethyl diethylene glycol, dialkyltriethylene glycol ethers, propylene glycol methyl ether, dipropyleneglycol methyl ether, tripropylene glycol methyl ether, propylene glycolmethyl ether acetate, dipropylene glycol methyl ether acetate, propyleneglycol n-propyl ether, dipropylene glycol n-propyl ether, propyleneglycol n-butyl ether, dipropylene glycol n-butyl ether, tripropyleneglycol n-butyl ether, propylene glycol diacetate, dipropylene glycoldimethyl ether, and mixtures thereof. In various preferred embodimentsof the present invention, suitable solvents include mono-alkyl ethers ofpropylene glycol and dipropylene glycol, and even more preferablymono-alkyl ethers of propylene glycol. In certain particularly preferredembodiments of the present invention, the solvent comprises propyleneglycol mono methyl ether.

In accordance with various embodiments of the present invention,solutions of any amount of a polyfunctional aziridine component in asuitable solvent, as described above, could be used, though generally atleast about 0.5% by weight of a polyfunctional aziridine component isuseful to achieve at least some improvement in adhesion and generallymore than 10% by weight provides no further improvement. In variouspreferred embodiments of the present invention, solutions containing 1to 10% by weight of a polyfunctional aziridine component, based on theweight of the solution, are used. In various more preferred embodimentsof the present invention, solutions containing 2.5 to 7.5% by weight ofa polyfunctional aziridine component, based on the weight of thesolution, are used. In certain even more preferred embodiments of thepresent invention, the polyfunctional aziridine component is present inthe solution in an amount of about 5% by weight.

Solutions for use in accordance with the various embodiments of thepresent invention can be prepared in any known manner by simplycombining a polyfunctional aziridine component in the desired amountwith a suitable non-reactive solvent, and allowing the polyfunctionalaziridine component to dissolve, preferably with mixing.

In the various embodiments of the present invention, a solution of apolyfunctional aziridine component in a suitable non-reactive solvent inaccordance with any of the aforementioned embodiments is applied to aproteinaceous substrate. Substrates upon which a solution can be appliedin accordance with the present invention include, but are not limitedto, fingernails, toenails and livestock hooves.

As previously mentioned, methods in accordance with various embodimentsof the present invention include applying a solution of a polyfunctionalaziridine component in a suitable non-reactive solvent to aproteinaceous substrate. Application of a solution can be accomplishedin a variety of ways, though preferably by brushing the solution ontothe substrate. Additional, suitable mechanisms by which a solution maybe applied to a proteinaceous substrate in accordance with variousembodiments of the invention include, but are not limited to spraying,dipping, and blotting. In various preferred embodiments of methods inaccordance with the present invention, a solution of a polyfunctionalaziridine component in a suitable non-reactive solvent is absorbed ontoa sponge or other foam applicator and blotted onto a proteinaceoussubstrate. Application of a solution in accordance with the variousembodiments of the present invention is preferably directed primarily tothe tip and edges of the proteinaceous substrate, for example, the tipand cuticle areas of a human fingernail. Preferably, the solution isapplied as thinly as possible, and ideally at a thickness of 10 micronsor less. In the context of the present invention, the application of athin coating of a solution of a polyfunctional aziridine component in asuitable non-reactive solvent refers to the absence of “pooling” orexcess solution which may drip from or accumulate at the tip or edge ofa substrate.

After a solution in accordance with any of the various embodiments ofthe present invention is applied to a proteinaceous substrate, variouspreferred methods in accordance with the present invention furtherinclude removing the aprotic solvent from the applied solution toprovide a primed substrate. Removing the aprotic solvent from theapplied solution can include evaporation, either under ambientconditions or with heating, for example, via a heat-lamp. Thepolyfunctional aziridine component bonds to the proteinaceous substrateby reaction of an aziridine moiety and any nucleophilic functional grouppresent on the proteinaceous substrate, such as, for example, carboxylicacid groups, amide groups, hydroxyl groups and sulfide groups ordegradation products thereof.

In various preferred embodiments of the present invention, methodsaccording to the invention can further include applying a topcoatcomposition to the primed substrate. As used herein, a “topcoatcomposition” includes, but is not limited to, decorative and protectivecoatings, additional adhesives and prosthetic materials, as well asmultilayer applications such as a colorcoat and a final clearcoat.Decorative and protective coatings suitable for use in accordance withvarious embodiments of the present invention can be water-based orlacquer-based polishes. Preferred decorative and protective coatings foruse in accordance with various embodiments of the present invention arewater-based. Preferably, a topcoat composition is applied to the primedsubstrate shortly after, and even more preferably, immediately afterremoval of the solvent from the solution of a polyfunctional aziridinecomponent in the solvent. Unreacted aziridine functionalities on theprimed substrate can then react with carboxyl groups or othernucleophilic groups in the topcoat composition providing improvedadhesion between the proteinaceous substrate and the topcoatcomposition.

The invention will now be described in further detail with reference tothe following non-limiting examples.

EXAMPLES

Improvement of Adhesive Strength Testing

Comparison 1: Evalution of Inventive Primer & Water-Based Nail Polishversus Current Market Leader Nitrocellulose Lacquer Based Nail PolishSytem.

Sixteen female subjects meeting the inclusion and exclusion criteria setforth below took part in the comparative evaluation. The inclusioncriteria were: (i) between the ages of 18 and 65 years, inclusive; (ii)must have regularly used nail enamel at least once per week; (iii) musthave had a relatively uniform nail length, which extended to or exceededthe fingertip; (iv) healthy nails; (v) completion of a medical historyform and the understanding and signing of an Informed Consent Form; (vi)considered dependable and had the intelligence to follow directions; and(vii) must avoid gardening during the evaluation study. The exclusioncriteria were: (i) no repaired nails; (ii) no recently removed tips orwraps; (iii) no onychophagy (nail biting), ridges and/or discoloration;(iv) no history of sensitivity to nail enamels or removers; (v) nooccupational limitations, i.e., chemist, use of industrial cleaners;(vi) no evidence of excessive, non-reparable breakage; (vii) not in anoccupation that pre-disposes nails to excessive breakage/exposure; and(viii) not pregnant or nursing.

The testing interval consisted of 8 days, with 4 evaluations. Subjectshad their nails manicured and cleaned. All evidence of nail enamel wasremoved by a Licensed Cosmetologist. Subjects washed their hands withmild soap and water, thoroughly drying them prior to test materialapplications.

All test products were shaken just prior to use. Subjects were assignednumbers. Even numbered subjects had a nail coating system according toan inventive embodiment applied to the nails of their right hands andthe comparative nail coating system applied to the nails of their lefthands. Conversely, odd numbered subjects had the inventive embodimentapplied to the nails of their left hands and the comparative nailcoating system applied to the nails of their right hands.

The Inventive nail coating system used in this comparison was asfollows: (i) inventive primer composition containing PZ-33 (apolyfunctional aziridine component, available from PolyAziridine, LLC,Medford, N.J.) in propylene glycol methyl ether, in an amount of 5% byweight of the solution, Lot 187601; (ii) Go Natural water-based polishcolor coat “I'm Looking Good”, Lot 188304 (Go Natural available from Madriver Science, McKinleyville, Calif.); and (iii) Go Natural water-basedtopcoat, Lot 183805.

The Comparative nail coating system used was as follows: (i) OPI's “ChipSkip” primer, Lot NT100; (ii) OPI's “Natural Nail Basecoat”, Lot NT T10;(III) OPI's Colorcoat “I'm Not Really A Waitress”, Lot NT H08; (iv)OPI's “Top Coat”, Lot NT T30. (OPI Product, Inc, North Hollywood,Calif.).

A very thin coat of the inventive primer or OPI primer and base coat wasapplied to all nails (according to the subject numbering describedabove), allowing it to dry for approximately 30 seconds or the time ittook to apply to all the fingernails. One thin coat of applicablecolorcoat was applied. A second thin coat of applicable colorcoat wasapplied and allowed to dry to the touch for 30 seconds. A generous coatof applicable topcoat was then applied and allowed to dry for 30seconds. The fingernails were then blown dry for 60 seconds, with a blowdryer set on warm heat/low blower setting. Subjects remained at thefacility for an additional 15 minutes to ensure adequate drying/curing.

Subjects were reminded not to use any nail products, base and/or topcoats, including color touch-up. Subjects were instructed not to immersetheir nails in hot/soapy water for at least 2 hours post application andto avoid activities that could damage their nails.

Evaluations were made for gloss on Days 0, 3, 5, and 7, and for chip andwear on Days 3, 5 and 7 by matching complimentary fingers on the leftand right hands and scoring the individual fingers. The LicensedCosmetologist conducted the evaluations.

The initial application of test materials revealed a perfect glossevaluation. Seven days post-application, the inventive nail coatingsystem significantly outperformed the comparative nail coating system,exhibiting less diminished gloss, less chipping and less diminishedwear. As shown by this comparison, embodiments of the present inventioncan provide water-based, non-toxic nail coatings that perform as well asthe market-leading nitrocellulose lacquer nail coating systems currentlyavailable to the consumer.

Comparison 2: Evaluation of Inventive Primer & Water-Based Nail Polishversus Water-Based Nail Polish without Inventive Primer.

An evaluation using a laboratory test protocol similar to that describedin Comparison 1, comparing water-based Go Natural nail polishes havingthe inventive primer solution used in Comparison 1 applied to the nailsubstrate before application, and the same water-based Go Natural nailpolishes without the use of the inventive primer solution, was carriedout over five (5) days on five (5) volunteer human subjects' fingernailsfor each polish tested. The overall average comparative results showthat the use of the inventive primer solution markedly improves theadhesion performance of the Go Natural nail polish by an average ofgreater than 15%.

Comparison 3: Evaluation of Inventive Primer & Nitrocellulose LacquerBased Nail Polish versus Nitrocellulose Lacquer Based Nail Polishwithout Inventive Primer.

An evaluation using a laboratory test protocol similar to that describedin Comparison 2, comparing acrylic lacquer based nail polishes havingthe inventive primer solution used in Comparison 1 applied to the nailsubstrate before application, and the same acrylic lacquer based nailpolishes without the use of the inventive primer solution, was carriedout over five (5) days on five (5) volunteer human subjects' fingernailsfor each polish tested. The overall average comparative results showthat the use of the inventive primer solution markedly improves theadhesion performance of the nitrocellulose lacquer-based nail polish byan average of greater than 15%.

As shown in the comparisons set forth above, the present inventionprovides improved adhesion of various topcoat compositions toproteinaceous substrates versus direct application of the topcoatcompositions to the substrate. Additionally as can also be seen fromComparison 1, the present invention can provide improved performancecompared to an existing market-leading system consisting of aconventional base coat, color coat, and topcoat marketed by OPI.

In Vitro Toxicity Testing:

Solutions of a polyfunctional aziridine component in a suitablenon-reactive solvent were evaluated for skin irritancy potentialutilizing the MatTek Corporation (Ashland, Mass.) EpiDerm in vitrotoxicity testing system.

MatTek's EpiDerm Skin Model consists of normal, human-derived epidermalkeratinocytes (NHEK) which have been cultured to form a multilayered,highly differentiated model of the human epidermis. Keratinocytes arecultured on specially prepared, permeable cell culture inserts. Thissystem closely parallels human skin. EpiDerm consists of highlyorganized basal, spinous, granular and cornified layers analogous tothose found in vivo. Epiderm cultured keratinocytes are mitotically andmetabolically active. EpiDerm, when used with the recommended cellmetabolism assay as carried out in these Examples, can quickly providetoxicological profiles. The procedure utilizes a water-soluble, yellow,tetrazolium salt (MTT{3-4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide}), whichis reduced by succinate dehydrogenase in the mitochondria of viablecells to a purple, insoluble formazan derivative. Substances whichdamage this mitochondrial enzyme inhibit the reduction of thetetrazolium salt. The amount of MTT reduced by a culture is thereforeproportional to the number of viable cells.

An inventive test solution was prepared by dissolving a pentaerythritoltris(3-aziridinopropionate) composition (PZ-33™ polyfunctionalaziridine, obtained from PolyAziridine LLC, Medford, N.J.) in propyleneglycol n-butyl ether in an amount of 5% by weight, based on thesolution.

After the appropriate tissue preparation according to the MatTek EpiDermmodel, for each dosage of the inventive solution, one-hundredmicroliters of the solution were deposited on a piece of filter paper.After drying, a circular portion of the exposed filter paper, thediameter of the MatTek Millicell, was cut out and added to theMillicells containing the EpiDerm samples so that the inventive solutionfilter paper surface contacted the tissue. Each dosage was thenmoistened with one-hundred microliters of distilled water to ensureinteraction between the solution-treated filter paper and the tissue.The six (6) well plates containing the dosed EpiDerm samples were thenincubated at 37° C., five (5) % carbon dioxide and ≧90% humidity. Afterthe appropriate exposure periods, each insert was individually removedfrom its plate and rinsed with phosphate buffered saline (PBS) to removeany residual material. Each was then rinsed a second time. Excess liquidwas shaken off and each EpiDerm sample was placed into 300 microlitersof MTT solution. The EpiDerm samples were then returned to theincubator. After the three (3) hour MTT exposure, each insert wasremoved and gently rinsed with PBS to remove any residual MTT solution.Excess PBS was shaken from each of the inserts, which were then blottedon the bottom using paper towels. The inserts were then each placed intoone (1) well of a 24 well extraction plate. Each insert was thenimmersed in two (2) milliliters of extraction solution overnight. Afterthe exposure, the liquid within each insert was decanted back into thewell from which it was taken. The remaining extractant solution was thenagitated and a 200 microliter aliquot of each extract was removed forevaluation. A Dynatech MR 4000 Automatic Microplate Reader was used todetermine the absorbance of each extract at 570 nm. With the absorbanceof the negative control defined as 100%, the percent absorbencies of thetest article were determined. The percentages listed below directlycorrelate with the cell metabolism in the EpiDerm samples.

TABLE 2 MatTek EpiDerm Toxicity Results. Article Percent Percent (% &Exposure) System Viability Inhibition (100% - 1 hr.) EpiDerm 112 −12(100% - 4.5 hr.) EpiDerm 76 24 (100% - 20 hr.) EpiDerm 98 2

For the article, a semi-log scale was used to plot the percentviabilities, on the linear y axis, versus the dosing times, on the log xaxis. By interpolation and where possible, the time at which the percentviability would be 50% (ET-50) was estimated.

The NB Code/Batch#: 187601; ID: 5% PZ 33 in PnB test article, at 100%*,elicited an ET-50 greater than 24 hours. According to MatTekCorporation, as a general guideline, the following groupings can be usedin assigning expected in vivo irritancy responses based on the ET-50results obtained using MatTek's EpiDerm:

TABLE 3 ET-50 (hrs) Expected In vivo Irritancv Example   <0.5 Severe,probably corrosive Conc. Nitric Acid 0.5-4  Moderate 1% Sodium DodecylSulfate  4-12 Moderate to Mild 1% Triton X-100 12-24 Very Mild BabyShampoo 24 Non-irritating 10% Tween 20

Under the conditions of this test, the NB Code/Batch#: 187601; ID: 5% PZ33 in PnB test article, at 100%*, elicited an ET-50 greater than 24hours and has an expected in vivo dermal irritancy potential in thenon-irritating range.

Human Skin Testing/Insult Patch Testing:

The potential of a primer composition in an accordance with anembodiment of the present invention to induce primary or cumulativeirritation and/or allergic contact sensitization of human skin wascarried out according to the following procedure.

Participants: Fifty-six (56) qualified subjects, male and female,ranging in age from 18 to 67 years, were selected for this evaluation.Fifty-four (54) subjects completed this study. The remaining subjectsdiscontinued their participation for various reasons, none of which wererelated to the application of the Inventive primer composition.

Inclusion Criteria for the Study: (i) Male and female subjects, age16^(a) and over; (ii) Absence of any visible skin disease which might beconfused with a skin reaction from the test material; (iii) Prohibitionof use of topical or systemic steroids and/or antihistamines for atleast seven days prior to study initiation; (iv) Completion of a MedicalHistory form and the understanding and signing of an Informed Consentform; and (v) Considered reliable and capable of following directions

Exclusion Criteria for the Study: (i) Ill health; (ii) Under a doctor'scare or taking medication(s) which could influence the outcome of thestudy; (iii) Females who are pregnant or nursing; and (iv) A history ofadverse reactions to cosmetics or other personal care products.

The Inventive primer composition evaluated in this study contained PZ-33(a polyfunctional aziridine component, available from PolyAziridine,LLC, Medford, N.J.) in propylene glycol n-butyl ether, in an amount of5% by weight of the solution.

Methodology: The upper back between the scapulae served as the treatmentarea. Approximately 0.2 ml of the Inventive primer composition, or anamount sufficient to cover the contact surface, was applied to the 1″×1″absorbent pad portion of a clear adhesive dressing and allowed tovolatilize for approximately 30 minutes. This was then applied to theappropriate treatment site to form a semi-occlusive patch.

Induction Phase: Patches were applied three (3) times per week (e.g.,Monday, Wednesday, and Friday) for a total of nine (9) applications. Thesite was marked to ensure the continuity of patch application. Followingsupervised removal and scoring of the first Induction patch,participants were instructed to remove all subsequent Induction patchesat home, twenty-four hours after application. The evaluation of thissite was made again just prior to re-application. If a participant wasunable to report for an assigned test day, one (1) makeup day waspermitted. This day was added to the Induction period.

With the exception of the first supervised Induction Patch reading, ifany test site exhibited a moderate (2-level) reaction during theInduction Phase, application was moved to an adjacent area. Applicationswere discontinued for the remainder of this test phase, if a moderate(2-level) reaction was observed on this new test site. Applicationswould also be discontinued if marked (3-level) or severe (4-level)reactivity was noted.

Rest periods consisted of twenty-four hours following each Tuesday andThursday removal, and forty-eight hours following each Saturday removal.

Challenge Phase: Approximately two (2) weeks after the final Inductionpatch application. a Challenge patch (identical to Induction patch) wasapplied to a virgin test site adjacent to the original Induction patchsite, following the same procedure described for Induction. TheInduction phase assesses initial adverse reactions (contact dermatitis)to the test material. Since most allergic reactions are induced byallergens during some previous exposure or series of exposures, theChallenge phase is used to determine if the exposure during theinduction phase did indeed create an allergic contact dermatitis. TheChallenge patch was removed and the site scored at the clinictwenty-four and seventy two hours post-application.

Methodology (continued): Evaluation Criteria (Erythema and additionalDermal Sequelae): 0 = No visible skin reaction 0.5 = Barely perceptible1 = Mild 2 = Moderate 3 = Marked 4 = Severe E = Edema D = Dryness S =Staining P = Papules V = Vesicles B = Bullae U = Ulceration Sp =Spreading

Erythema was scored numerically according to this key. If present,additional Dermal Sequelae were indicated by the appropriate letter codeand a numerical value for severity.

The results of each participant are set forth below in the table. Withone exception, observations remained within normal limits throughout thetest interval. Subject #17 exhibited mild (1) erythema and edemaseventy-two and ninety-six hours post challenge application.Unfortunately, this subject was unable to participate in a rechallengepatch test to better define the nature and reproducibility of thisresponse.

The results of this Insult patch testing, as shown below in the table,indicate that the Inventive primer composition tested does not have astatistically significant potential for dermal irritation or allergiccontact sensitization. Since no other dermal squelae (spreading beyondthe site, vesiculation) was observed, this response can be consideredclinically insignificant.

Table of Insult Patch Test Results: Subject Induction Phase VirginChallenge Site Number 24*hr 1 2 3 4 5 6 7 8 9 24*hr 72 hr 1 0 0 0 0 0 00 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 4 0 0 00 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 0 0 0 0 6 0 0 0 0 0 0 0 0 0 0 0 0 70 0 0 0 0 0 0 0 0 0 0 0 8 0 0 0 0 0 0 0 0 0 0 0 0 9 0 0 0 0 0 0 0 0  2^(E2A) 0 0 0 10 0 0 0 0 0 0 0 0 0 0 0 0 11 0 0 0 0 0 0 0 0 0 0 0 0 120 0 0 0 0 0 0 0 0 0 0 0 13 0 0 0 0 0 0 0 0 0 0 0 0 14 0 0 0 0 0 0 0 0 00 0 0 15 0 0 0 0 0 0 0 0 0 0 0 0 16 0 0 0 0 0 0 0 0 0 0 0 0 17 0 0 0 0 00 0 0 0 0 0 1^(E1) 1^(E1)* 18 0 0 0 0 0 0 0 0 0 0 0 0 19 0 0 0 0 0 0 0 00 0 0 0 20 0 0 0 0 0 0 0 0   2^(E2A) 0.5^(D1) 0 0 21 0 0 0 0 0 0 0 0 0 00 0 22 0 0 DID NOT COMPLETE 23 0 0 0 0 0 0 0 0 0 0 0 0 24 0 0 0 0 0 0 00 0 0 0 0 25 0 0 0 0 0 0 0 0 0 0 0 0 26 0 0 0 0 0 0 0 0 0 0 0 0 27 0 0 00 0 0 0 0 0 0 0 0 28 0 0 0 0 0 0 0 0 0 0 0 0 29 0 0 0 0 0 0 0 0 0 0 0 030 0 0 0 0 0 0 0 0 0 0 0 0 31 0 0 0 0 0 0 0 0 0 0 0 0 32 0 0 0 0 0 0 0 00 0 0 0 33 0 0 0 0 0 0 0 0 0 0 0 0 34 0 0 0 0 0 0 0 0 0 0 0 0 35 0 0 0 00 0 0 0 0 0 0 0 36 0 0 0 0 0 0 0 0 0 0 DNC 37 0 0 0 0 0 0 0 0 0 0 0 0 380 0 0 0 0 0 0 0 0 0 0 0 39 0 0 0 0 0 0 0 0 0 0 0 0 40 0 0 0 0 0 0 0 0^(D1) 0 0 0 0 41 0 0 0 0 0 0 0 0 0 0 0 0 42 0 0 0 0 0 0 0 0 0 0 0 0 430 0 0 0 0 0 0 0 0 0 0 0 44 0 0 0 0 0 0 0 0 0 0 0 0 45 0 0 0 0 0 0 0 0 00 0 0 46 0 0 0 0 0 0 0 0 0 0 0 0 47 0 0 0 0 0 0 0 0 0 0 0 0 48 0 0 0 0 00 0 0 0 0 0 0 49 0 0 0 0 0 0 0 0 0 0 0 0 50 0 0 0 0 0 0 0 0 0 0 0 0 51 00 0 0 0 0 0 0 0 0 0 0 52 0 0 0 0 0 0 0 0 0 0 0 0 53 0 0 0 0 0 0 0 0 0 00 0 54 0 0 0 0 0 0 0 0 0 0 0 0 55 0 0 0 0 0 0 0 0 0 0 0 0 56 0 0 0 0 0 00 0 0 0 0 0 24* = Supervised removal of 1^(st) Induction and ChallengePatch A = Changed to adjacent site *= Observation conducted 96 hourspost challenge application E = Edema D = Dryness DNC = Did not completestudy

Both the MatTek EpiDerm model toxicity testing and the human skin insultpatch testing carried out using an inventive example of a solution inaccordance with an embodiment of the present invention, show that thesolutions are non-toxic, non-irritant and safe. This is surprising andunexpected given the dangers associated with azacyclopropane andpolyethylenimine.

It will be appreciated by those skilled in the art that changes could bemade to the embodiments described above without departing from the broadinventive concept thereof. It is understood, therefore, that thisinvention is not limited to the particular embodiments disclosed, but itis intended to cover modifications within the spirit and scope of thepresent invention as defined by the appended claims.

What is claimed is:
 1. A method comprising: (a) providing a solution ofa polyfunctional aziridine component in a non-reactive solvent; and (b)applying the solution to a proteinaceous substrate.
 2. The methodaccording to claim 1, further comprising: (c) removing the non-reactivesolvent from the solution applied to the proteinaceous substrate toprovide a primed substrate; and (d) applying a topcoat composition tothe primed substrate.
 3. The method according to claim 2, whereinremoving the non-reactive solvent comprises allowing the non-reactivesolvent to evaporate from the solution.
 4. The method according to claim1, wherein the non-reactive solvent comprises propylene glycol monoalkylether, wherein the polyfunctional aziridine component comprisespentaerythritol tris(3-aziridinopropionate), and wherein thepolyfunctional aziridine component is present in an amount of 2.5 to7.5% by weight, based on the solution.
 5. The method according to claim2, wherein the non-reactive solvent comprises propylene glycol monoalkylether, wherein the polyfunctional aziridine component comprisespentaerythritol tris(3-aziridinopropionate), wherein the polyfunctionalaziridine component is present in an amount of 2.5 to 7.5% by weight,based on the solution, and wherein the topcoat composition comprises awater-based nail polish.
 6. The method according to claim 1, wherein theproteinaceous substrate is selected from the group consisting offingernails and toenails.
 7. The method according to claim 1, whereinthe solution contains monomeric ethylenimine in an amount below a toxiclevel.
 8. The method according to claim 1, wherein the polyfunctionalaziridine component is present in an amount of at least about 0.5% byweight, based on the solution.
 9. The method according to claim 1,wherein the polyfunctional aziridine component is present in an amountof 1 to 10% by weight, based on the solution.
 10. The method accordingto claim 1, wherein the polyfunctional aziridine component is present inan amount of 2.5 to 7.5% by weight, based on the solution.
 11. Themethod according to claim 1, wherein the polyfunctional aziridinecomponent comprises a mixture of two or more compounds having two ormore aziridine functionalities and the component has an averageaziridine functionality of ≧3.0.
 12. The method according to claim 1,wherein the polyfunctional aziridine component comprises a compoundselected from the group consisting of trimethylolpropanetris(3-2-methylaziridino)propionate, trimethylolpropanetris(3-aziridinopropionate), pentaerythritoltris(3-aziridinopropionate), and mixtures thereof.
 13. The methodaccording to claim 1, wherein the polyfunctional aziridine componentcomprises pentaerythritol tris(3-aziridinopropionate).
 14. The methodaccording to claim 13, wherein the polyfunctional aziridine component ispresent in an amount of 2.5 to 7.5% by weight, based on the solution.15. The method according to claim 1, wherein the non-reactive solventcomprises a dialkyl diglycol ether.
 16. The method according to claim 1,wherein the non-reactive solvent comprise a propylene glycol monoalkylether.
 17. The method according to claim 1, wherein the non-reactivesolvent comprises propylene glycol monomethyl ether.
 18. The methodaccording to claim 1, wherein the non-reactive solvent comprise apropylene glycol monoethyl ether.
 19. The method according to claim 1,wherein the non-reactive solvent comprise a propylene glycol monopropylether.
 20. The method according to claim 1, wherein the non-reactivesolvent comprise a propylene glycol monobutyl ether.
 21. The methodaccording to claim 1, wherein the non-reactive solvent comprise apropylene glycol monoalkyl ether selected from the group consisting ofpropylene glycol monomethyl ether, propylene glycol monoethyl ether,propylene glycol mono-n-propyl ether, propylene glycol monoisopropylether, propylene glycol mono-n-butyl ether, propylene glycolmono-t-butyl ether, and mixtures thereof.